Process for hydrodesulfurization employing a platinum-alumina catalyst



F. G. CIAPETTA' ET AL 2,885,352 PROCESS FOR HYDRODESULFURIZATION EMPLOYING A PLATINUM-ALUMINA CATALYST Filed June 10,1955 2 SheetsSheet 2 United States Patent 2,885,352 PROCESS FOR HYDRODESULFURIZATION EM- PLOYING A PLATINUM-ALUMINA CATALYST Frank G. Ciapetta, Silver Spring, Md., and Harry L.

Coonradt, Woodbury, and William E. Garwood, Haddonfield, N.J., assignors to Socony Mobil Oil Company, Inc., a corporation of New York Application June 10, 1953, Serial No. 360,662 4'Claims. (Cl. 208-217) This invention relates to the refining of petroleum hydrocarbons. It is more particularly concerned with a catalytic process for the removal of sulfur compounds, i.e., the desulfurization of petroleum hydrocarbons. The invention also relates to combined processes wherein petroleum fractions are desulfurized and subsequently subjected to further conversion operations.

As is well known to those familiar with the art, many petroleum hydrocarbon fractions such as gasolines, gas oils, naphthas, lubricating oils, etc., contain relatively large amounts of sulfur compounds which effect stability and impair the usefulness of the fractions. Thus, for example, gasoline which contains relatively large amounts of sulfur compounds, i.e., sour gasoline, must be sweetened. In general, the sweetening process is effected by means of chemical treatments, which are relatively expensive. Similarly, in the case of other sulfurcontaining petroleum fractions, such as fuel oils, lubricating oils, etc., chemical additives must be used to stabilize the fraction and to overcome the deleterious effect of sulfur compounds. It has been proposed to effect desulfurization, i.e., the removal of sulfur compounds, in whole or in part, by treating the petroleum hydrocarbon fraction with hydrogen in the presence of catalysts, such as the oxides or sulfides of molybdenum and tungsten, cobalt molybdate, etc. As is also well known to those familiar with the art, it is generally considered that the platinum and palladium series metals are readily poisoned by sulfur compounds. Accordingly, the use of such metals has been avoided when operations have been carried out on sulfur-containing charge stocks.

It has now been found that desulfurization of sulfurcontaining petroleum fractions can be effected without substantially altering the other characteristic properties of the petroleum fractions, by means of a simple and economical process. Contrary to the teaching of the prior art, it has been discovered that such petroleum fractions can be desulfurized, substantially completely, by contacting the fraction with a catalyst comprising a metal of the platinum or palladium series supported on inert carriers, in the presence of hydrogen. Also contrary to the teaching of the prior art, it has been discovered that such catalysts are not poisoned by sulfur, under the operating conditions of this process.

Accordingly, it is an object of this invention to provide a desulfurization process which is simple and economical. Another object is to provide a process for desulfurizing sulfur-containing petroleum fractions, without substantially altering the other characteristic properties thereof. A specific object is to provide a process for desulfurizing sulfur-containing petroleum fractions without substantially altering the other characteristic properties thereof, by contacting them with a solid catalyst in the presence of hydrogen. A more specific object is to pro vide a process for desulfurizing sulfur-containing hydrocarbon zfractions without substantially altering the other characteristic properties thereof, which comprises contacting them with a catalyst which includes platinum or palladium series metals on an inert carrier, in the presence of hydrogen. Another specific object is to provide a combined process wherein a sulfur-containing petroleum fraction is first subjected to desulfurization in the presence of hydrogen and platinum or palladium series metal catalysts without substantially altering the other characteristic properties thereof, and subsequently the thus-desulfur-ized petroleum fraction is converted to useful products, such as by reforming or by hydrocracking. Other objects and advantages of this invention will become apparent to those skilled in the art, from the following detailed description considered in conjunction with the figures, wherein:

Figure 1 presents a series of curves representing the relationship between the temperature and percent desulfurization, and between the temperature and the percent conversion, of a typical sulfur-containing gas oil, when subjected to the process of this invention;

Fig. 2 presents a series of curves representing therelationship between the temperature and percent desulfurization, and between the temperature and the percent conversion of a typical sulfur-containing gas oil, when subjected to the action of a catalyst comprising platinum on a cracking base; and

Fig. 3 presents a diagrammatic representation of an embodiment of this invention which involves a combined desulfurization and conversion operation.

In general, the present invention provides a desulfurization process, which comprises contacting a petroleum fraction, which contains sulfur compounds, with a catalyst that includes a metal of the platinum or palladium series supported on an inert carrier, at a temperature varying between about 500 F. and about 850 F., in the presence of hydrogen under a pressure varying between about pounds per square inch gauge and about 3000 ounds per square inch gauge, at a liquid hourly space velocity of between about 0.1 and about 10, and with a hydrogen to hydrocarbon molar ratio varying between about 1 and about 80.

The process of this invention is applicable to any petroleum fraction which contains sulfur compounds. Thus, it can be applied to fractions such as gasoline, kerosine, fuel oil, cycle stocks, diesel fuels, gas oils, lubricating oils, and residual fuels, e.g., bunker fuel. The process is especially applicable for the desulfurization of distillate fuels, and for the desu-lfurization of sulfur-containing charge stocks for cracking or for reforming operations.

As was stated hereinbefore, the catalysts used in the process of this invention comprise platinum or palladium metals supported upon inert carriers. The metals, so supported, are the metals of the platinum and the palladium series of metals. These are the metals having atomic numbers of 44-46, inclusive, and 76-78, inclusive. Platinum and palladium are especially preferred. The amount of platinum or palladium series metals in the catalyst can vary between about 0.05 percent and about 20 percent, by weight of the catalyst, and preferably between about 0.1 percent and about 5 percent.

As has been mentioned hereinbefore, the carriers for the catalyst used in the process of this invention are inert carriers. The inert carriers are support materials which are inert with respect to the cracking of hydrocarbons, i.e., materials which are not effective in catalytic cracking operations, under the operating conditions of the process of this invention. Such carriers, as is well known to those familiar with the art, include single oxides of the metals of groups IIA, IIIB, and IVA and B of the periodic arrangement of the elements U. Chem. Educ., 16, 409 (1939)]. These oxides are inert to cracking. Nonlimiting examples thereof include alumina, silica, magnesia, titania, etc. Other materials known to be inert to cracking, such as activated carbon, coke, pumice, charcoal, etc., and natural materails, e.g., bauxite, inert earths, etc., are also contemplated as carriers herein.

The carrier can be in anyshape or form, such as rods, spheres, pellets, etc.

The carrier should be dried. Thereafter, the platinum or palladium series of metal is deposited thereon, in any suitable manner. A preferred method is to admix with the dried carrier an aqueous solution of an acid of the metal, for example, chloroplatinic or chloropalladic acid, or of the ammonium salt of the acid, of suitable concentration. The mixture is then dried and treated with hydrogen at elevated temperatures to reduce the chloride to the metal and to activate the catalyst. It has been found that the catalysts contemplated herein are surprisingly resistant to poisoning by sulfur.

After a long service period, the catalyst may require regeneration and reactivation. This can be accomplished by manymethods. A particularly feasible regeneration process involves passing air or oxygen through a bed of the catalyst at temperatures of 900950 F., commencing with a gas of low oxygen content (about 2 percent) and gradually increasing the oxygen content until pure air or oxygen is used. After treatment with hydrogen, the catalyst is fullyreactivated.

A novel feature of the process of this invention is that maximum desulfurization is achieved at relatively low temperatures, so that the other characteristic properties of the charge stock are not substantially altered. In other words, regardless of the nature of the charge stock, maximum desulfurization is effected at temperatures wherein little or no reforming, cracking, and the like occur. This is illustrated in Fig. 1.

In Fig. 1, curve A represents the relationship between the temperature and the percent desulfurization of a gas oil derived from a Kuwait crude, which contains 1.2 percent sulfur. The data for curve A are based on runs wherein desulfurization' was effected by contacting the gas oil with a catalyst comprising 1.6 percent platinum on an alumina carrier. In all of the runs, on which the curve is based, the molar ratio of hydrogen to gas oil was 10, the liquid hourly space velocity was 1, and the hydrogen pressure was 500 pounds per square inch gauge. Also in Fig. 1 curve A sets forth the relationship between the temperature and the percentage of the Kuwait gas oil which is converted to lower boiling hydrocarbons. Curve A is based upon data obtained in the same runs upon which curve A is based.

In Fig. 1 it will be noted that the maximum amount of desulfurization is achieved at temperatures varying between about 600 F. and about 750 F. At these temperatures, it is to be noted, very little cracking of the gas oil Was effected. It is to be noted, however, that-desulfurization temperatures will vary slightly with other charge stocks, and that some desulfurization can occur at-temperatures as low as about500 F. and as high as about 850 F. Accordingly, temperature of operation for process ofthis invention Will vary generally between 500- F. and about 850 F. In preferred practice, however, thetemperature will vary between about 600 F. and about 750 F The. desulfurization of other sulfur-containing hydrocarbon fractions, such as naphthas, gasoline, kerosine, and lubricating oils, is likewise effected within the temperature ranges set forth hereinbefore. Accordingly, desulfurization of these materials is achieved at sufficiently lowtemperatures so that the alteration of the other characteristic properties of the materials is relatively small.

Inorder to avoid altering the other characteristic properties of the sulfur-containing charge stock, as by cracking, reforming, etc,, it is essential that the carrier has no cracking activity. This is illustrated by the curves in Fig. 2. In Fig. 2, curve Cshows the relationship between the percent desulfurization and the operating temperature in the desulfurization of a Kuwait gas oil, in the presence of a catalyst comp-rising about '2 percent, by weight, of platinumdeposited upon a silica-alumina cracking component. Curve C sets forth the relationship between the temperature and the percent of the gas oil which is converted to lower-boiling hydrocarbons. Curve C is based upon data obtained in the same runs upon which curve C is based. In the runs upon which curves C and C are based, the charge stock and the operating conditions were the same as were used in the runs upon which curves A and A (Fig. 1) were based; he only ifference being in the catalyst. It will be noted that, when the carrier is a cracking component (Fig. 2), a high percentage of cracking conversion is efiected at the temperatures at which substantially complete desulfurization occurs. In contrast thereto, virtually no cracking takes place when the carrier is inert (Fig. 1, curves A and A). Accordingly, the advantages of the present process will be at once apparent.

The hydrogen pressure can vary between about pounds per square inch gauge and about 3000 pounds per square inch gauge, but it is preferred to operate under pressures of between about 200 pounds per square inch gauge and about 1500 pounds per square inch gauge. The molar proportion of hydrogen to hydrocarbon can be between about 1 and about 80, preferably between about 3 and about 40. The process should be operated at a liquid hourly space velocity (volume of liquid hydrocarbon charge per hour per volume of catalyst) varying between about 0.1 and about 10, and preferably between about 0.1 and about 4.

The desulfurization process of this invention can be carried out in any vessel suitable for catalytic processes. It can be operated batch-wise, but continuous operation is preferred. The process can utilize a moving bed of catalyst, or it can be performed in a fluidized process. However, the present process is particularly adapted to fixed bed operation, and such operation is preferred.

The following specific example is presented for the purpose of illustrating the desulfurization process of this invention. It must be strictly understood, however, that this invention is not to be limited by the reactants and conditions used in the example, or by the operations an d manipulations involved. As those skilled in the art will appreciate other conditions, charge stocks, and catalysts can be used, as is described hereinbefore.

EXAMPLE A gas oil derived from a Kuwait crude had the following characteristics:

A.P. I. gravity 37.5 ASTM distillation:

Sulfur, wt. percent 1.20

Table I Runswlth 1.6% Pt on A Temperature, T. 503 654 Volume percent conversion to ter r carbons 1.4 5:7 Wt; percent sulfur ineffluent 0.97 0.11 Percent desulfurization 62 As was mentioned hereinbefore, the desulfurization process of this invention can be combined with other operations, such as reforming and hydrocracking. Suitable reforming and hydrocracking operations, using platinum or palladium catalysts, are described in co-pending applications, Serial Numbers 351,151, 351,152; 351,312; and 351,313, all filed on April 27, 1953, all now abandoned; and Serial Number 418,166, filed March 23, 1954, a continuation-in-part of Serial Number 351,151. In general, the hydrocracking catalysts comprise 0.1-2O per-- cent, by weight, of metals of the platinum and palladium series (Atomic Nos. 44-46 and 76-78, inclusive) supported upon acidic refractory oxide carriers having a high cracking activity, such as silica-alumina, silica-zirconia, alumina-boria, etc. The oxide supports are synthetic composites of oxides .of at least two metals of groups IIA, IIIB, and IVA and B of the periodic arrangement of the elements. The hydrocracking operation will be effected at temperatures varying between about 500 F. and about 750 F., preferably between about 600 F. and about 750 F. The liquid hourly space velocity utilized is between about 0.1 and about 10, and preferably between about 0.1 and about 4. The hydrogen pressure will vary between about 100 pounds per square inch gauge and about 5000 pounds per square inch gauge, preferably between about 350 pounds per square inch gauge and about 2500 pounds per square inch gauge. The molar proportion of hydrogen to hydrocarbon charge will vary between about 2 and about 80, preferably between about 5 and about 50. It is ordinarily preferred that the hydrocracking operation be carried out in the liquid phase, or mixed vapor and liquid phase.

' As was indicated hereinbefore, the cracking charge stocks utilizable in the process of this invention can vary over wide ranges. The process is applicable to the entire crude petroleum, which may, or may not, be deasphalted. Any of the usual charge stocks ordinarily suitable for thermal or catalytic cracking processes can be used. Additionally, the process is applicable to high sulfur-containing fractions, to cycle stock derived from cracking of hydrocarbons, and to residual fractions. The utilizable charge stocks are defined in co-pending application, Serial No. 351,151, supra, and in Serial Number 418,166, the continuation-in-part thereof. Briefly, the gas oils boil between about 300 F. and about 700 F. Cycle stocks boil between about 400 F. and about 850 F. Residual fractions boil at about 750 F. and upwards. Reference should be made to the co-pending application for further definitions of the charge.

The reforming operations are carried out in the presence of platinumor palladium-containing reforming catalysts. These catalysts can comprise 0.05-2 percent, by weight, of platinum or palladium deposited upon a composite carrier comprising, for example, silica-alumina, I

silica-zirconia, silica-alumina-zirconia, alumina-boria and the like. These catalysts have been fully described and defined in the prior art. Especially preferred, however, are the catalysts described in co-pending applications Serial Nos. 351,152; 351,312; and 351,313, filed April 27, 1953, in which applications, the inventor herein is a coinventor. In these applications, three general types of catalysts are described. One catalyst includes between about 0.05 percent, by weight, and about 2 percent, by

weight, of platinum or palladium deposited upon silica which has composited therewith between about 1.3 percent, by weight, and about 3 percent, by weight, of alumina, and which has a surface area varying between about 80 square meters per gram and about 120 square meters per gram, preferably between about 90 and about cent, by weight, and about 2.3 percent, by weight, of alumina, and which has a surface area varying between about 350 square meters per gram and about 700 square meters per gram, preferably between about 400 and about 650 square meters per gram, and an activity index vary ing between about 6 and about 15, preferably between about 8 and about 12. A third catalyst includes between about 0.05 percent, by weight, and about 2 percent, by weight, of platinum or palladium deposited upon alumina which has composited therewith between about 0.01 percent, by Weight, and about 15 percent, by weight, of silica, preferably between about 0.2 percent and about 10 percent, by weight, and which 'has a surface area varying between about 50 square meters per gram and about 500 square meters per gram, preferably between about and about 400 square meters per gram, and an activity index varying between about 6 and about 20, preferably between about 7 and about 15.

The reforming operation will be carried out at temperatures of between about 700 F. and about 1000 F., preferably between about 725 F. and about 950 F. The liquid hourly space velocity will vary between about 0.1 and about 10, preferably between about 0.5 and about 4. The hydrogen pressure will vary between about 100 pounds per square inch gauge and about 1000 pounds per square inch gauge, preferably between about 350 pounds per square inch gauge and about 700 pounds per square inch gauge. The molar proportion of hydrogen to hydrocarbon charge will be between about 1 and about 20, preferably between about 4 and about 12.

The processes described in the co-pending application, of course, can be carried out using sulfur-containing charge stocks. It was found that the presence of sulfur did not poison the catalysts. In reforming, the highsulfur charge stocks do, however, lower the activity of the catalysts.

In practice, however, it may be preferred to desulfurize a high-sulfur charge material before reforming it or cracking it, in order to operate the reforming or cracking process to effect maximum conversions. Especially in the case of reforming in accordance with the processes described in co-pending applications, Serial Numbers 351,152; 351,312; and 351,313, supra, the desulfurization process of this invention can be combined therewith, with a maximum overall efliciency of operation. There is a net production of hydrogen from the reforming process, i.e., there is excess hydrogen. This hydrogen can be used to supply whatever hydrogen is required in the desulfurization process. This is illustrated in Fig.3.

This figure presents a diagrammatic arrangement for a typical combined desulfurization and reforming process. The apparatus involved includes a reactor 10 suited for desulfurization by contact with solid catalysts, a gas separator 11, a gas scrubber 12, a reforming unit 13 suitable for hydroforming operations, a gas separator 14, and a fractionating tower 15, together with the necessary de vices for pumping, compressing, heat exchange, etc.

In operation, a charge stock, such as naphtha, straightrun gasoline, etc. (boiling between about 60 F. and about 450 F.) containing sulfur compounds is charged to the process through pipe 16. Hydrogen gas in suitable proportions is supplied from pipes 17 and 18. Then, the charge and hydrogen are passed to a compressing and 'pumping unit 19, wherein they are compressed and pumped via pipe 20 through a heating unit 21. The combined charge is passed from the heating unit 21, through pipe 22 into the desulfurization reactor 10. In the reactor the charge is contacted with a platinum or palladium metal catalyst, as defined hereinbefore, to efiiect conversion of the sulfur compounds into hydrogen sulfide gas. The efiluent from the reactor, comprising desulfurized charge stock, hydrogen, and hydrogen sulfide is passed to the gas separator 11 through pipe 23. In the gas separator, the gases are separated from the liquid, desulfurized charge. This desulfurized charge is conveyed to the reforming operation by means of pipe 24. The gases, chiefly hydrogen and hydrogen sulfide can be removed from the gas separator 11 and conveyed, through pipe 25, into a gas scrubber 12, wherein the hydrogen sulfide gas is removed, as by scrubbing with ethanolamines. The scrubbing fluid containing the hydrogen sulfide can be removed through pipe 26. The remaining gas, chiefly hydrogen, can be recycled via pipe 17.

The desulfurized charge stock, in pipe 24, is commingled with hydrogen in suitable proportions, hydrogen being supplied from pipe 30. The charge and hydrogen are compressed in compressing and pumping unit 31, and thence pumped, via pipe 32, through a heater 33. Then,

the heated charge is passed into the hydroforming reactor 13, through pipe 34. In the reactor 13, the charge is subjected to hydroforming by contacting it with a bed of a suitable platinum or palladium catalyst, such as those described in the co-pending applications referred to hereinbefore. The effluent from the reactor 13 is conveyed via pipe 35 into a gas separator 14. There the gases are separated from the liquid product. The liquid product is removed through pipe 36 and depressurized in depressuring zone 37. The product is thence conveyed via pipe 38 to the fractionating tower 15. In the fractionating tower 15, the product is separated into several fractions. The gaseous hydrocarbons are removed through pipe 39. The reformate, i.e., the gasoline is removed via pipe 40. Bottoms can be withdrawn through pipe 41. Alternatively, the bottoms can be recycled via pipe 42, by suitable manipulation of valves 43, 44, and 45.

As mentioned hereinbefore, there will be a net production of hydrogen in the reforming process. The hydrogen which is separated in the gas separator 14 is removed by means of pipe 46. By suitable operation of valves 47, 48 and 49, a portion of the hydrogen in pipe 46 is supplied to satisfy the inlet requirements of the reforming operation, via pipe 30. The remainder of the hydrogen in pipe 46 is passed to the desulfurization operation through pipe 18. Hydrogen needed to initiate the process can be supplied to the system via pipe 50, by suitable manipulation of valves 51, 52 and 53. Once the combined process is in operation, external hydrogen will not be required. Indeed, there will often be excess hydrogen produced in the process. This excess hydrogen can be removed, suitably, via pipe 50, the charging of hydrogen therethrough being discontinued.

Another embodiment of this invention involves a combined desulfurization and hydrocracking operation. The process involved is similar to that just described, with several exceptions. The charge stock used for this operais any suitable cracking stock such as a high-boiling petroleum crude fraction, a gas oil, a residual stock, a cycle stock, etc. The cracking stock is desulfurized substantially as described, in conjunction with the combined reforming-desulfurization process. The liquid product from the gas separator 11 is conveyed via pipe 24 to a cracking unit where it is admixed with hydrogen, compressed, and pumped, as in the reforming process. The reactor 13, however, is now a catalytic cracking unit adapted to contact operation. The catalyst contained therein will be a platinum or palladium metal catalyst of the type described in co-pending application, Serial Number 315,151, supra, and in Serial Number 418,166, supra, the continuation-in-part thereof. The eflluent from the cracking reactor 13 is subjected to gas separation, depressurized, and charged to a fractionator 15, as aforedescribed. The operation of the fractionator 15, however, is somewhat different. Any gaseous products which are produced are removed via pipe 39. Through pipe 40 is removed a light naphtha fraction, comprising C -C hydrocarbons. A heavy naphtha fraction, boiling up to about 400 F., is removed through pipe 60. This fraction can be hydroformed to produce high octane gasoline. The residual material from the fractionation, chiefly uncracked charge stock, is removed through pipe 41 and recycled through pipe 42.

There will not be an excess of hydrogen produced in the hydrocracking operation. Accordingly, all of the hydrogen gas removed through pipe 46 is recycled via pipe 30. The additional hydrogen required for the cracking and the hydrogen needed for the desulfurization are supplied from another source through pipe 50. The source of this hydrogen can be a reforming operation which is tied into the system by means of pipe 60.

In a further embodiment of a cracking process, as is described in co-pending application, Serial Number 351,153, filed April 27, 1953, a whole petroleum crude can be fractionated to separate a straight-run gasoline and a cracking charge stock. The straight-run gasoline can be desulfurized and reformed. The cracking stock can be desulfurized, hydrocracked, and then reformed. In this type of operation, the net yield of hydrogen from the two reforming operations will be suflicient to satisfy the hydrogen requirements of the hydrocracking and of the hydrodesulfurization operations. Thus, the combined, overall process will require little or no addition of hydrogen from extraneous sources, once it is in full operation.

Although the present invention has been described in conjunction with preferred embodiments it is to be understood that modifications and variations may be resorted to, without departing from the spirit and scope of this invention, as those skilled in the art will readily understand. Such variations and modifications are considered to be within the purview and scope of the appended claims.

What is claimed is:

1. A desulfurization process which comprises contacting a sulfur containing petroleum fraction with a catalyst that consists of between about 0.05 percent by weight and about 20 percent by weight of a metal selected from the group consisting of metals having atomic numbers of between 44 and 46 inclusive, and between 76 and 78 inclusive, supported on an inert carrier, at a temperature varying between about 500 F. and about 850 F., in the presence of hydrogen under a pressure varying between about pounds per square inch gauge and about 3000 pounds per square inch gauge, at a liquid hourly space velocity of between about 0.1 and about 10, and with a hydrogen to hydrocarbon molar ratio varying between about 1 and about 80.

2. A desulfurization process which comprises contacting a sulfur containing petroleum fraction with a catalyst that consists of between about 0.1 and about 5 percent platinum by weight, supported upon an inert carrier, at a temperature varying between about 600 F. and about 750 F., in the presence of hydrogen under a pressure varying between about 200 pounds per square inch gauge and about 1500 pounds per square inch gauge, at a liquid hourly space velocity of between about 0.1 and about 4, and with a hydrogen to hydrocarbon molar ratio varying between about 3 and about 40.

3. A desulfurization process which comprises contacting a sulfur containing gas oil fraction with a catalyst that consists of between about 0.1 percent by Weight and about 5 percent by weight of platinum supported upon an inert carrier, at a temperature varying between about 600 F. and about 750 F., in the presence of hydrogen under a pressure varying between about 200 pounds per square inch gauge and about 1500 pounds per square inch gauge, at a liquid hourly space velocity of between about 0.1 and about 4, and with a hydrogen to hydrocarbon molar ratio varying between about 3 and about 40.

4. A desulfurization process which comprises contacting a sulfur containing gas oil fraction with a catalyst that consists of bewteen about 0.1 percent by weight and about 5 percent by weight of platinum deposited upon an alumina carrier, at a temperature varying between about 600 F. and about 750 F., in the presence of hydrogen under a pressure varying between about 200 pounds per square inch gauge and about 1500 pounds per square inch gauge, at a liquid hourly space velocity of between about 0.1 and about 4, and with a hydrogen to hydrocarbon molar ratio varying between about 3 and about 40.

References Cited in the file of this patent UNITED STATES PATENTS Gwynn Mar. 9, 1937 Jones May 4, 1948 UNITED STATES PATENT OFFICE CERTIFICATE OF CDRRECTION Patent No. 2,885 ,352 May 5, 1959 Frank G. Ciapetta et al.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 4, line 63, for natalys" read e catalyst column 6, line 31,-

for "epplication' read. applications column '7 line 50, for "opera read operation column 8 line 70, for "bewteen" read between y Signed and sealed this 1st day oi September 1959.

( L) Attest:

KARL H., AXLINE. ROBERT C. WATSON Attesting Oflicer Commissioner of Patents 

1. A DESULFURIZATION PROCESS WHICH COMPRISES CONTACTING A SULFUR CONTAINING PETROLEUM FRACTION WITH A CATALYST THAT CONSISTS OF BETWEEN ABOUT 0.05 PERCENT BY WEIGHT AND ABOUT 20 PERCENT BY WEIGHT OF A METAL SELECTED FROM THE GROUP CONSISTING OF METALS HAVING ATOMIC NEMBERS OF BETWEEN 44 AND 46 INCLUSIVE, AND BETWEEN 76 AND 78 INCLUSIVE, SUPPORTED ON AN INERT CARRIER, AT A TEMPERATURE VARYING BETWEEN ABOUT 500* F. AND ABOUT 850* F., IN THE PRESENCE OF HYDROGEN UNDER A PRESSURE VARYING BETWEEN ABOUT 100 POUNDS PER SQUARE INCH GAUGE AND ABOUT 3000 POUNDS PER SQUARE INCH GAUGE, AT A LIQUID HOURLY SPACE VELOCITY OF BETWEEN ABOUT 0.1 AND ABOUT 10, AND WITH A HYDROGEN TO HYDROCARBON MOLOR RATION VARYING BETWEEN ABOUT 1 AND ABOUT
 80. 